Arrangement for measuring the length of oblong objects

ABSTRACT

This invention relates to the measuring and cross-cutting of tree stems advanced by feed rolls. Upstream of the cross-cutting member two measuring rollers are pressed resiliently against the stem in diametrically opposed places. One of the measuring rollers is connected to a transmitter for signaling the stem length corresponding to the rotation of the measuring roller to a control unit. When a desired stem length has been achieved, the control unit stops the feed rolls and starts the movement of the cross-cutting member against the stem.

United States Patent 1191 Lindblom 1 1March 13, 1973 ARRANGEMENT FORMEASURING 3,642,041 2 1972 Hamilton 8! Eli. ..144/3 D x THE LENGTH OFOBLONG OBJECTS 2,843,165 7/1958 Sherron ..144/246 F X 3,587,681 6/1971 w11161 a1. ..144 2 2 Inventor: KaflThm'e LmdbhmAma Swede" 3,542,099 111970 (Z5011 ..144 3 D 3,457,974 7/1969 Mitten ..l44/246 R X [73]Assignee: Ostbergs Fabriks AB, Alfta, Sweden P E A d R J h rzmaryxam1ner n rew u1 asz [22] Ffled' 1971 1 Assistant Examiner-James F. CoanPP No.1 1941364 Attorney Ralph B. Parker et a1.

[30] Foreign Application Priority Data I [57] 0 ABSTRACT Nov. 6, 1970Sweden ..1s034 7o This invention relates to the measuring andCrosscutting of tree stems advanced by feed rolls. Upstream 52 US. Cl...144/3 1), 83/369, 144/2 2, 9f the cross-cutting member two measuringrollers are 144/246 6 pressed resiliently against the stem indiametrically 0p- [51] Int. Cl ..B27b 25/02, B27b 31/00 p se places Oneof the measuring rollers is con? [58] Field of Search ..144/3 D, 2 Z,246 R, 246 E, nected to a transmitter for signaling the stern length144/246 F, 246 G, 309 AC; 143/55 R, 55 A, corresponding to the rotationof the measuring roller 55 B; 83/208, 369 to a control unit. When adesired stem length has been achieved, the control unit stops the feedrolls and [56] References Cited starts the movement of the cross-cuttingmember t th I UNITED STATES PATENTS agams e S em 3,448,647 6/1969 M1116161 a1. ..s3 20s x 5 Claims 1 D'awmg? Figure 3,108,509 10/1963 Felix..83/369 X ARRANGEMENT FOR MEASURING THE LENGTH OF OBLONG OBJECTS Thisinvention relates to an arrangement for measuring and cross-cutting treestems or the like advanced in their longitudinal direction by a feedunit, for example feed rolls.

In arrangements of this type in many cases a counting mechanism or thelike is connected to the drive rolls for the timber, for measuring thelength of the timber advanced between the rolls. In those cases when thetimber offers resistance to its advancement, there is a risk that thedrive rolls will slip whereby a misleading timber length will beindicated. ,A typical example of roll feed of timber when resistance maybe encountered is the delimbing of trees which now usually is carriedout by mechanical equipment, in such a way, that the drive or feed rollspull the tree through a ring of knives shearing off limbs and branches.Usually the stem is cross-cut to desired lengths subsequent to itsdelimbing, and in those cases when the cross-cutting is to be carriedout automatically, the function of the crosscutting member is controlledby the counting mechanism of the feed rolls. The slightest slipobviously will result in cutting stem pieces which are too short, andwhich either must be rejected or sold at a substantially reduced price.It should be obvious to the expert to try to increase the engagement ofthe feed rolls so as to eliminate the slip risk. This, however, requiressuch substantial roll pressures or the arrangement of spikes orcorresponding grip members projecting from the rolls, that there is riskthat the surface wood will be damaged seriously. Also in this case,thus, a reduced market value or rejection of the timber can be expected.

This problem is solved in a unique way by the arrangement according tothe invention which is characterized in that it comprises twodiametrically opposed measuring rollers resiliently pressed against thestem surface and placed immediately upstream of a crosscutting memberserving for cross-cutting the stem, one of the measuring rollers beingconnected to a first transmitter for signaling the stem lengthcorresponding to the rotation of the measuring roller to a control unit,which is adapted, in response to the signal that a predetermined stempiece length has been achieved, to stop the feed unit and to start themovement of the cross-cutting member againstthe stem.

The invention is described in greater detail in the following, withreference to the accompanying drawing showing in a schematic way a planeview of a combined delimbing and cross-cutting machine equippedaccording to the invention.

In the FIGURE, 1 designates the last part of a tree stem, which by feedrolls 2 and 3 is driven to the right in the FIGURE. Upstream of therolls (i.e. to the left in the FIGURE) a delimbing unit is shownsymbolized by two shearing knives 4 and 5, and immediately upstreamthereof is indicated a knife 6 for cutting off the tree top rated aswaste. At a substantial distance downstream of the drive rolls, to theside of stem 1, a cross-cutting knife 7 is mounted so as to be able to.move perpendicularly to and from the stem for cross-cutting it to piecesof desired length. Immediately upstream of the cutting plane of theknife 7 a roller 8 is mounted for supporting the stem. Said supportingroller v8 is driven synchronously with the feed rolls.

According to the invention, two diametrically opposed measuring rollers9 and 10 engage with the stem 1 in a place somewhat upstream of thesupporting roller 8. The measuring rollers are each mounted forfreerunning at one end of arms 11 and 12 respectively, which extendsubstantially parallel with the stem and which are rotatably mounted atfixed points 13 and 14 respectively at their other ends. From said otherends of the arms there extend in a lower plane (relative to the plane ofthe drawing) levers 15 and 16, respectively between the ends of which adouble-acting hydraulic means 17 is connected. A pressure accumulator Tis connected to the pressure line 18 of the means 17 to contract themeans and thereby to urge the measuring rollers 9, 10 against thestem 1. The dash-dotted line K between the pressure lines of thehydraulic means and roll 3 indicates in a schematic way that themeasuring rollers are operated synchronously with the feed rolls, sothat the measuring rollers and the feed rolls are separatedsimultaneously to receive the stem I laid down from above and thereafterto be applied simultaneously to the stem. The dash-dotted yoke B betweenthe measuring rollers 9 and 10 represents a device, which indicates thedistance between the rollers and thereby the stem diameter.

A first transmitter G is connected to the measuring roller 9 in order tosend a mechanical or electrical signal, to a first input of a controlunit S for example one metering impulse or signal per 7.5 mm stemlength, which signal corresponds to the rotation of the roller 9 andthus to the stem advance length corresponding thereto. A secondtransmitter G is connected to the yoke B for the stern diameter in orderto send to a second input on the control unit S a signal correspondingto the stem diameter. The two transmitters further send their signals toa combined integrator-indicator device V. The control unit S has twooutputs for actuating the movement of the cross-cutting knife 7 and alsothe feed rollers 2 and 3 to and from the stem 1.

The arrangement described above operates in the way as follows.

When a tree stem has been positioned between the knives 4 and 5 and feedrollers 2 and 3, then in the control unit 8 there are set or stored thedesired lengths of the timber pieces and the minimum diameter thereof,below which the stern would not be classified as timber but rather aspulp wood.

.Subsequent to the application of knives and rolls, the drive unit forthe feed rolls is started, so that the stem end portion is guided by thearms 11 and 12 which are urged against the stem into contact with themeasuring resilient and slip-free engagement with the tree stern,

and stem) and also on the stem diameter at any moment.

The control unit, when it has received from the transmitter G the numberof (mechanical or electrical) metering impulses corresponding to thedesired timber length, sends a signal to the feed rolls 2 and 3 forstopping the feed and a signal to the cross-cutting knife 7 forinstantaneous movement against the stem to cross-cut the same. From thetime when the stem feed was commenced, to the cross-cutting operation,the transmitters G and G also have continuously sent their informationto the integrator-indicator device V which, on the basis of the lengthand diameter information received, progressively integrates the volumeof the timber piece. The value of this volume at the moment ofcross-cutting can be read from an indicator at V.

The operation described above is repeated up to the situation shown inthe FIGURE, where it is assumed that the timber length l is next in turnto be separated. If the diameter transmitter G records the value of theminimum diameter initially in the control unit before the timber lengthinitially preset in the control unit S and continuously measured by thelength transmitter G has been achieved, then the control units reactsimmediately on receipt of this signal from the transmitter G by orderingthe feed 2 and 3 to stop rolls and the cross-cutting knife 7 to,cross-cut. Without a signal from G however, that the minimum diameterhas been reached, the cross-cutting, of course, will be carried out indue course with a full length of the timber.

Also the pulp wood lengths following thereafter can be preset in thecontrol unit, and the operation will be the same as during thecross-cutting of timber.

In the FIGURE is shown, for reason of simplicity, only a single lengthII for pulp wood. The tree top III, which cannot be utilized as timber,mostly is cut off by the top knife 6, which is operated separately. Whenthereafter the rear end of the pulp wood piece [I leaves the feed rolls2 and 3, it continues to be advanced by the supporting roller 8 whilebeing guided laterally by the still engaging measuring rollers 9 and 10.The engagement of said rollers also prevents the last length II fromtilting downwardly too violently about the supporting roller 8 in thefinal phase of the discharge.

Even when it is normally expected that the stem feed will be stoppedimmediately when the feed rolls receive the order from the control unitto stop for crosscutting, one cannot protect oneself against a forwardslip of the stem or a defect in the drive transmission. An unintendedcontinued stem feed, when the crosscutting knife 7 engage the stem, maycause theknife to break, which would involve great risks to the operatorand an expensive breakdown for knife exchange. Therefore, the controlunit can be so adapted upon receipt of a further metering impulse(corresponding, for example, to said 7.5 mm feed of the stem) from thetransmitter G, still driven by the measuring rollers, in addition to theusual number of impulses stipulated for the preset timber length, toinhibit or interrupt the movement of knife 7 against the stem.

The arrangement described above, thus, provides a guarantee for accuratedesired timber and pulp wood lengths, and thereby also for accuratevolume values, with a minimum of waste, while with conventional systems,by which the measuring of length was dependent on the rotation of thefeed rolls, one often had to reduce the value of valuable timber parts,i.e. of the timber lengths with the greatest diameter, because whenworking with spruces it is just these parts which carry the thickestbranches and therefore have given rise to marked slipping tendenciesand, thus, to much too short timber lengths.

The invention is not restricted to the embodiment described above, butdifferent modifications can be imagined within the scope of theinvention. In principle, for example, a single measuring roller would besufficient, though then the automatic volume determination may providespecial problems. Furthermore, the elastic application of the measuringrollers (roller) could be effected in a way other than the one shown,for example by means of a spring arrangement acting upon either swinginglevers (as shown) for the measuring rollers or on holders supporting therollers, which holders may be guided in guide means perpendicular to thepath of motion of the stem.

The invention, of course, could be applied also to the known stemprocessing arrangements where instead of feed rolls drag tongs areusedfor skidding the stem through the delimbing unit. The measuringprinciples of the invention could in general be utilized advantageouslyfor determining the dimension of wood other than tree stems or of otheroblong objects, such as metal or plastic pipes etc.

What I claim is:

1. An arrangement for measuring and cross-cutting tree stems advanced intheir longitudinal directions by a feed unit, comprising a cross-cuttingmember for cutting the stem, two rollers mounted for engaging the stemat diametrically opposed positions immediately upstream of saidcross-cutting member, support means for resiliently urging said rollersagainst the stem surface, a first transmitter connected to one of saidrollers, and a control unit connected to the feed unit and to saidcross-cutting member, the output of said transmitter being coupled tothe input of the control unit for signaling to said control unit thestem length corresponding to the rotation of said one of said rollers,the control unit delivering, in response to the signal that the stem hadreached a predetermined section length, an output signal to stop thefeed unit, and an output signal to start the operation of saidcross-cutting member for cutting the stem.

2. An arrangement according to claim 1 and further comprising a deviceincluding means for continuously sensing the distance between the tworollers corresponding to the varying stem diameter, a secondtransmitter, the output of said device being connected to said secondtransmitter, an indicator connected to both the output of said firsttransmitter and the output of said second transmitter to indicate thevolume of the stem section, said second transmitter also having anoutput connected to said control unit for signaling, in response to astem diameter below a predetermined minimum, a forced stop of the feedunit and a start of said cross-cutting member.

3. An arrangement according to claim 1 wherein said first transmitter inresponse to continued rotation of the rollers caused by an unintendedadvance of the stem after the cross-cutting member has received an orderfrom the control member to start operation, sends a signal to thecontrol unit to stop the motion of the cross-cutting member.

4. An arrangement according to claim 1 wherein said support meanscomprises a pair of arms, each of the rollers being mounted at one endof one of said arms, the other end of each arm being pivotally mountedat a stem.

5. An arrangement according to claim 4,, and further comprising apressure accumulator disposed in the feed line to said hydraulic meansto permit resilient operafixed point, and hydraulic means mountedbetween the 5 of Said Tonerstwo arms for resiliently urging the rollersagainst the

1. An arrangement for measuring and cross-cutting tree stems advanced intheir longitudinal directions by a feed unit, comprising a cross-cuttingmember for cutting the stem, two rollers mounted for engaging the stemat diametrically opposed positions immediately upstream of saidcross-cutting member, support means for resiliently urging said rollersagainst the stem surface, a first transmitter connected to one of saidrollers, and a control unit connected to the feed unit and to saidcross-cutting member, the output of said transmitter being coupled tothe input of the control unit for signaling to said control unit thestem length corresponding to the rotation of said one of said rollers,the control unit delivering, in response to the signal that the stem hadreached a predetermined section length, an output signal to stop thefeed unit, and an output signal to start the operation of saidcross-cutting member for cutting the stem.
 1. An arrangement formeasuring and cross-cutting tree stems advanced in their longitudinaldirections by a feed unit, comprising a cross-cutting member for cuttingthe stem, two rollers mounted for engaging the stem at diametricallyopposed positions immediately upstream of said cross-cutting member,support means for resiliently urging said rollers against the stemsurface, a first transmitter connected to one of said rollers, and acontrol unit connected to the feed unit and to said cross-cuttingmember, the output of said transmitter being coupled to the input of thecontrol unit for signaling to said control unit the stem lengthcorresponding to the rotation of said one of said rollers, the controlunit delivering, in response to the signal that the stem had reached apredetermined section length, an output signal to stop the feed unit,and an output signal to start the operation of said cross-cutting memberfor cutting the stem.
 2. An arrangement according to claim 1 and furthercomprising a device including means for continuously sensing thedistance between the two rollers corresponding to the varying stemdiameter, a second transmitter, the output of said device beingconnected to said second transmitter, an indicator connected to both theoutput of said first transmitter and the output of said secondtransmitter to indicate the volume of the stem section, said secondtransmitter also having an output connected to said control unit forsignaling, in response to a stem diameter below a predetermined minimum,a forced stop of the feed unit and a start of said cross-cutting member.3. An arrangement according to claim 1 wherein said first transmitter inresponse to continued rotation of the rollers caused by an unintendedadvance of the stem after the cross-cutting member has received an orderfrom the control member to start operation, sends a signal to thecontrol unit to stop the motion of the cross-cutting member.
 4. Anarrangement according to claim 1 wherein said support means comprises apair of arms, each of the rollers being mounted at one end of one ofsaid arms, the other end of each arm being pivotally mounted at a fixedpoint, and hydraulic means mounted between the two arms for resilientlyurging the rollers against the stem.